Abstract: An optical counting device of the type used for counting mineral particles suspended within a liquid, for example, ore float tailings. The counting device includes a plate imprinted with a gridiron in its mid-portion, an absorbent doughnut pad removably supported upon the plate and conformed such that the gridiron on the plate is in register with the open space of the doughnut pad and a doughnut housing having an open space at its mid-portion defining a counting chamber in register with the gridiron and open space of the absorbent pad. The counting chamber facilitates a random distribution of suspended particles over the gridiron, while the suspending medium is withdrawn into the absorbent pad.